Current query write buffer is 256 bytes, on stack. In comparison, theddebug_query boot-arg is 1024. Allocate the buffer off heap, andenlarge it to 4096 bytes, big enough for ~100 queries (at 40 byteseach), and error out if not. This makes it play nicely with largequery sets (to be added later). The buffer should be enough for mostuses, and others should probably be split into subsets.